US20080142913A1 - Z offset mems devices and methods - Google Patents
Z offset mems devices and methods Download PDFInfo
- Publication number
- US20080142913A1 US20080142913A1 US11/610,050 US61005006A US2008142913A1 US 20080142913 A1 US20080142913 A1 US 20080142913A1 US 61005006 A US61005006 A US 61005006A US 2008142913 A1 US2008142913 A1 US 2008142913A1
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- base
- gap
- mechanism layer
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
- B81C1/00182—Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
Definitions
- MEMS processing techniques create structures that are symmetric in the z axis (out of the wafer's surface) but can vary in the x and y axes (in the plane of the wafer's surface).
- creating asymmetry in the z-axis can be performed by deflecting with stiction plates or by selective thinning. Deflecting with stiction plates leads to devices which are sensitive to z motion, but is not easily implemented for multiple z-offsets in both the positive and negative z directions and also requires more steps and additional processing layers, thereby costing more money.
- Selective thinning is performed by thinning one set of teeth of a comb drive in the Z-direction, but this requires an extra mask and additional etches, and it is also rather inaccurate.
- One method of more easily creating asymmetry requires a top and a bottom cover enclosing the mechanism layer of the MEMS device to produce asymmetry in the negative and positive z directions.
- Some uses for MEMS devices require an exposed mechanism layer, and a top cover is incompatible with these uses.
- a microelectromechanical system (MEMS) device with a mechanism layer having a first part and a second part, and a base for attaching the mechanism layer.
- the mechanism layer is bonded to the base, and then an electrically conductive or semi-conductive material is used to deflect one of the first and second parts in the negative z direction until it contacts the base.
- a voltage is then applied through the electrically conductive material to bond the part to the base, and the electrically conductive material is removed, thereby creating z axis asymmetry without the need for a top cover.
- FIGS. 1A and 1B are top views of alternate embodiments of mechanism layers formed in accordance with the present invention.
- FIGS. 2A , 2 B, and 2 C illustrate various intermediate structures produced by a method according to the present invention
- FIG. 3 is a side view of a MEMS device according to the present invention.
- FIG. 4 is a block diagram of a method according to the present invention.
- FIG. 1A is a top view of an example mechanism layer 12 formed according to the present invention.
- the mechanism layer 12 includes walls 5 , 6 , 7 , 8 , a first movable portion 14 , a second movable portion 16 , and a fixed portion 18 .
- the first movable portion 14 is attached to walls 7 , 8 by flexure 15 (also torsional flexure or hinge), the second movable portion 16 is attached to walls 7 , 8 by flexure 17 , and the fixed portion 18 is attached to walls 7 , 8 by flexures 19 .
- FIG. 1B is a top view of an alternate embodiment of a mechanism layer 48 .
- the mechanism layer 48 includes walls 50 , 52 , 54 , 56 , a movable portion 64 attached to walls 54 , 56 by flexure 60 , and a fixed portion 62 attached to walls 54 , 56 by flexures 58 .
- FIGS. 2A , 2 B, and 2 C illustrate side views of various intermediate structures of a microelectromechanical system (MEMS) device 10 formed in accordance with one embodiment of the invention.
- FIG. 2A shows the mechanism layer 12 of FIG. 1A .
- the mechanism layer 12 is made of silicon.
- a base 20 with a top surface 21 , a gap 22 , and a gap surface 23 is also shown.
- the base 20 is made of glass.
- the depth of the gap 22 equals the desired z-offset distance of the fixed portion 18 .
- the gap 22 is formed by wet etching or other processes known to those have ordinary skill in the art.
- FIG. 2B shows the mechanism layer 12 and the base 20 after bonding the mechanism layer 12 to the top surface 21 .
- anodic bonding may be used to bond the mechanism layer 12 to the top surface 21 .
- the base 20 and mechanism layer 12 are made of different materials, appropriate bonding techniques known to those having ordinary skill in the art may be used.
- flexures 15 and 17 allow movement of the movable portions 14 , 16 .
- FIG. 2C shows the base 20 with the fixed portion 18 of the mechanism layer 12 being displaced down into contact with the gap surface 23 by an electrically conductive or semi-conductive material 24 , preferably highly doped silicon.
- the electrically conductive material 24 is sized and shaped such that it may be used to displace the fixed portion 18 but not the first and second movable portions 14 , 16 . While the electrically conductive material 24 is in contact with the fixed portion 18 and the fixed portion 18 is in contact with the gap surface 23 , a voltage V and a pressure P are applied between the base 20 and the fixed portion 18 to effect bonding of the fixed portion 18 to the gap surface 23 . After bonding, the electrically conductive material 24 is removed, leaving the finished structure 26 of FIG. 3 (note that walls 7 , 8 are not shown for clarity).
- FIG. 4 A block diagram 28 of an example method according to the present invention is shown in FIG. 4 .
- a base is masked and etched to form a gap.
- a mechanism layer is masked and etched to form the various structures of the mechanism layer.
- the mechanism layer is bonded to the base.
- a portion of the mechanism layer is deflected into the gap of the base until it contacts a surface of the gap.
- the deflected portion is bonded to the base.
Abstract
Description
- Standard microelectromechanical systems (MEMS) processing techniques create structures that are symmetric in the z axis (out of the wafer's surface) but can vary in the x and y axes (in the plane of the wafer's surface). Presently, creating asymmetry in the z-axis can be performed by deflecting with stiction plates or by selective thinning. Deflecting with stiction plates leads to devices which are sensitive to z motion, but is not easily implemented for multiple z-offsets in both the positive and negative z directions and also requires more steps and additional processing layers, thereby costing more money. Selective thinning is performed by thinning one set of teeth of a comb drive in the Z-direction, but this requires an extra mask and additional etches, and it is also rather inaccurate. One method of more easily creating asymmetry requires a top and a bottom cover enclosing the mechanism layer of the MEMS device to produce asymmetry in the negative and positive z directions. Some uses for MEMS devices require an exposed mechanism layer, and a top cover is incompatible with these uses.
- Thus, there exists a need for methods to easily form z-offsets in MEMS devices without completely enclosing the MEMS device.
- A microelectromechanical system (MEMS) device with a mechanism layer having a first part and a second part, and a base for attaching the mechanism layer. The mechanism layer is bonded to the base, and then an electrically conductive or semi-conductive material is used to deflect one of the first and second parts in the negative z direction until it contacts the base. A voltage is then applied through the electrically conductive material to bond the part to the base, and the electrically conductive material is removed, thereby creating z axis asymmetry without the need for a top cover.
-
FIGS. 1A and 1B are top views of alternate embodiments of mechanism layers formed in accordance with the present invention; -
FIGS. 2A , 2B, and 2C illustrate various intermediate structures produced by a method according to the present invention; -
FIG. 3 is a side view of a MEMS device according to the present invention; and -
FIG. 4 is a block diagram of a method according to the present invention. -
FIG. 1A is a top view of anexample mechanism layer 12 formed according to the present invention. Themechanism layer 12 includeswalls movable portion 14, a secondmovable portion 16, and a fixedportion 18. The firstmovable portion 14 is attached to walls 7, 8 by flexure 15 (also torsional flexure or hinge), the secondmovable portion 16 is attached to walls 7, 8 byflexure 17, and thefixed portion 18 is attached to walls 7, 8 byflexures 19. -
FIG. 1B is a top view of an alternate embodiment of amechanism layer 48. Themechanism layer 48 includeswalls walls 54, 56 byflexure 60, and afixed portion 62 attached towalls 54, 56 byflexures 58. -
FIGS. 2A , 2B, and 2C illustrate side views of various intermediate structures of a microelectromechanical system (MEMS)device 10 formed in accordance with one embodiment of the invention.FIG. 2A shows themechanism layer 12 ofFIG. 1A . Themechanism layer 12 is made of silicon. Abase 20 with atop surface 21, agap 22, and agap surface 23 is also shown. Thebase 20 is made of glass. The depth of thegap 22 equals the desired z-offset distance of thefixed portion 18. Thegap 22 is formed by wet etching or other processes known to those have ordinary skill in the art. -
FIG. 2B shows themechanism layer 12 and thebase 20 after bonding themechanism layer 12 to thetop surface 21. In the case of asilicon mechanism layer 12 and aglass base 20, anodic bonding may be used to bond themechanism layer 12 to thetop surface 21. When thebase 20 andmechanism layer 12 are made of different materials, appropriate bonding techniques known to those having ordinary skill in the art may be used. After bonding,flexures movable portions -
FIG. 2C shows thebase 20 with thefixed portion 18 of themechanism layer 12 being displaced down into contact with thegap surface 23 by an electrically conductive orsemi-conductive material 24, preferably highly doped silicon. The electricallyconductive material 24 is sized and shaped such that it may be used to displace thefixed portion 18 but not the first and secondmovable portions conductive material 24 is in contact with the fixedportion 18 and the fixedportion 18 is in contact with thegap surface 23, a voltage V and a pressure P are applied between thebase 20 and the fixedportion 18 to effect bonding of thefixed portion 18 to thegap surface 23. After bonding, the electricallyconductive material 24 is removed, leaving the finishedstructure 26 ofFIG. 3 (note that walls 7, 8 are not shown for clarity). - A block diagram 28 of an example method according to the present invention is shown in
FIG. 4 . At afirst block 30, a base is masked and etched to form a gap. At asecond block 32, a mechanism layer is masked and etched to form the various structures of the mechanism layer. At ablock 34, the mechanism layer is bonded to the base. At ablock 36, a portion of the mechanism layer is deflected into the gap of the base until it contacts a surface of the gap. At ablock 38, the deflected portion is bonded to the base. - Note that the method of the present invention may be combined with the methods disclosed in co-pending and jointly owned U.S. patent application Ser. No. 11/360,870, filed on Feb. 23, 2006 and titled “Z OFFSET MEMS DEVICE,” herein incorporated by reference, to enable offsets in the positive and negative z directions without including a top cover. Offsets in the negative z direction can be produced by the methods of the present invention, and offsets in the positive z direction can be produced by the methods of the “Z OFFSET MEMS DEVICE” application.
- While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
Claims (18)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/610,050 US7487678B2 (en) | 2006-12-13 | 2006-12-13 | Z offset MEMS devices and methods |
EP07122530.4A EP1932803B1 (en) | 2006-12-13 | 2007-12-06 | MEMS device with Z-axis asymetry |
JP2007321964A JP5512926B2 (en) | 2006-12-13 | 2007-12-13 | Z-offset MEMS device and method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/610,050 US7487678B2 (en) | 2006-12-13 | 2006-12-13 | Z offset MEMS devices and methods |
Publications (2)
Publication Number | Publication Date |
---|---|
US20080142913A1 true US20080142913A1 (en) | 2008-06-19 |
US7487678B2 US7487678B2 (en) | 2009-02-10 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/610,050 Expired - Fee Related US7487678B2 (en) | 2006-12-13 | 2006-12-13 | Z offset MEMS devices and methods |
Country Status (3)
Country | Link |
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US (1) | US7487678B2 (en) |
EP (1) | EP1932803B1 (en) |
JP (1) | JP5512926B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8171793B2 (en) | 2008-07-31 | 2012-05-08 | Honeywell International Inc. | Systems and methods for detecting out-of-plane linear acceleration with a closed loop linear drive accelerometer |
US20120119612A1 (en) * | 2010-11-15 | 2012-05-17 | Tessera MEMS Technologies, Inc. | Motion controlled actuator |
CN109319729A (en) * | 2017-07-31 | 2019-02-12 | 英飞凌技术德累斯顿有限责任公司 | Offset is formed in the inter-digital capacitor of microelectromechanical systems (MEMS) device |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8404568B2 (en) * | 2008-06-27 | 2013-03-26 | Honeywell International Inc. | Systems and methods for fabricating an out-of-plane MEMS structure |
US20100187667A1 (en) * | 2009-01-28 | 2010-07-29 | Fujifilm Dimatix, Inc. | Bonded Microelectromechanical Assemblies |
US8053265B2 (en) * | 2009-02-06 | 2011-11-08 | Honeywell International Inc. | Mitigation of high stress areas in vertically offset structures |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5666258A (en) * | 1993-02-18 | 1997-09-09 | Siemens Aktiengesellschaft | Micromechanical relay having a hybrid drive |
US20040036132A1 (en) * | 2002-06-13 | 2004-02-26 | Coventor, Inc. | Micro-electro-mechanical system (MEMS) variable capacitor apparatuses and related methods |
US20050002079A1 (en) * | 2003-03-22 | 2005-01-06 | Novotny Vlad J. | MEMS devices monolithically integrated with drive and control circuitry |
US20050074919A1 (en) * | 2000-12-07 | 2005-04-07 | Reflectivity, Inc. | Methods for depositing, releasing and packaging micro-electromechanical devices on wafer substrates |
US20050264452A1 (en) * | 2003-08-27 | 2005-12-01 | Tomoyasu Fujishima | Antenna and method of making the same |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3869438B2 (en) * | 2004-08-09 | 2007-01-17 | サンテック株式会社 | MEMS device, manufacturing method thereof, and optical device |
US7516661B2 (en) | 2006-02-23 | 2009-04-14 | Honeywell International Inc. | Z offset MEMS device |
-
2006
- 2006-12-13 US US11/610,050 patent/US7487678B2/en not_active Expired - Fee Related
-
2007
- 2007-12-06 EP EP07122530.4A patent/EP1932803B1/en active Active
- 2007-12-13 JP JP2007321964A patent/JP5512926B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5666258A (en) * | 1993-02-18 | 1997-09-09 | Siemens Aktiengesellschaft | Micromechanical relay having a hybrid drive |
US20050074919A1 (en) * | 2000-12-07 | 2005-04-07 | Reflectivity, Inc. | Methods for depositing, releasing and packaging micro-electromechanical devices on wafer substrates |
US20040036132A1 (en) * | 2002-06-13 | 2004-02-26 | Coventor, Inc. | Micro-electro-mechanical system (MEMS) variable capacitor apparatuses and related methods |
US20050002079A1 (en) * | 2003-03-22 | 2005-01-06 | Novotny Vlad J. | MEMS devices monolithically integrated with drive and control circuitry |
US20050264452A1 (en) * | 2003-08-27 | 2005-12-01 | Tomoyasu Fujishima | Antenna and method of making the same |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8171793B2 (en) | 2008-07-31 | 2012-05-08 | Honeywell International Inc. | Systems and methods for detecting out-of-plane linear acceleration with a closed loop linear drive accelerometer |
US20120119612A1 (en) * | 2010-11-15 | 2012-05-17 | Tessera MEMS Technologies, Inc. | Motion controlled actuator |
US8604663B2 (en) * | 2010-11-15 | 2013-12-10 | DigitalOptics Corporation MEMS | Motion controlled actuator |
CN109319729A (en) * | 2017-07-31 | 2019-02-12 | 英飞凌技术德累斯顿有限责任公司 | Offset is formed in the inter-digital capacitor of microelectromechanical systems (MEMS) device |
Also Published As
Publication number | Publication date |
---|---|
EP1932803A3 (en) | 2012-05-23 |
JP2008246663A (en) | 2008-10-16 |
JP5512926B2 (en) | 2014-06-04 |
EP1932803A2 (en) | 2008-06-18 |
US7487678B2 (en) | 2009-02-10 |
EP1932803B1 (en) | 2016-08-10 |
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